Keeping Watch
In science-fiction productions from "Star Trek" to the movie "Supernova," starships find themselves orbiting giant stars that are about to explode. Scientists know just when the explosion will occur, though, so the ship can speed away just in the nick of time.
So far, though, astronomers can't tell us when the next supergiant star will explode. They can give us a range; in the case of the star Betelgeuse, for example, they know that it'll happen sometime in the next 10,000 years. But there's nothing obvious on the surface of a star that tells us when it's about to blow.
That's because the explosion is driven by events far below the star's surface. The star's core consumes all of its nuclear fuel, then collapses. The outer layers fall onto the core, then rebound and blast into space at around one-tenth of the speed of light.
But astronomers hope that they eventually may be able to identify a supernova explosion before it happens.
They might look for "starquakes" rippling across the star's surface, for example. They might also look for outbursts of particles called neutrinos, which are produced when the core collapses. Or they might look for outbursts of "starspots" - magnetic storms driven by changes in the star's magnetic field.
If these methods work out, then astronomers may be able to keep a close watch on a star for hours or days before it explodes - all from the comfort and safety of home.
Script by Damond Benningfield, Copyright 2005
For more skywatching tips, astronomy news, and much more, read StarDate magazine.
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